Message-ID: <417C991C.2070806@pobox.com>
Date: Mon, 25 Oct 2004 02:11:40 -0400
From: Jeff Garzik <jgarzik@pobox.com>
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
       Greg KH <greg@kroah.com>
CC: Linux Kernel list <linux-kernel@vger.kernel.org>,
       Linux-pm mailing list <linux-pm@lists.osdl.org>
Subject: Re: Concerns about our pci_{save,restore}_state()
References: <1098677182.26697.21.camel@gaston>
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Benjamin Herrenschmidt wrote:
>  - What about saving/restoring more registers ? I'm not sure wether it
> should be the responsibility of the driver to save and restore things
> above dword 15, but we should at least deal with the case of P2P bridges
> who have more "standard" registers


This is a key concern of mine.

The _driver_ is the only entity that knows really how much space to 
save/restore, and the generic versions are obviously _not_ sufficient to 
support:

* hardware errata such as S3 Trio, where _reading_ or writing certain 
registers in the standard range cause a system lockup

* saving/restoring the standard-defined capability lists, which 
certainly could extend way beyond what's stored now

* saving/restoring the new PCI-Express 4K config area

This is _clearly_ something that should be decided upon in the driver. 
The PCI layer should _only_ present standard helper functions, and maybe 
a standard storage space that works for most drivers; not force all 
drivers through a narrow funnel.

	Jeff


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